Numerous devices which are useful for the automated assembly of products have been successfully used for many years. In each instance, automated assembly devices have been employed with a view toward increasing the efficiencies and accuracies of the methods, procedures, and processes which are followed during the manufacture and the assembly of a completed product. Indeed, the vast majority of consumer products are now manufactured on assembly lines which incorporate automated assembly devices.
It is easy to appreciate that as the complexity of a manufactured product increases, there may also be a commensurate increase in the complexity of the machines that are required to manufacture the product. For example, many products, including printed circuit boards, require that small assembly components be accurately positioned and then inserted. The process of positioning becomes increasingly difficult as smaller assembly components are used, where the assembly components have irregular or varying shapes, and/or where the components are fragile.
One type of device which has been successfully utilized as part of an automated assembly system is the linear voice coil actuator. Actuators of this type include an electromagnetic coil and a fixed-pole magnet. Electric current applied to the electromagnetic coil causes the coil to generate a magnetic field. The magnetic field generated by the electromagnetic coil interacts with the magnetic field generated by the fixed-pole magnet and causes the electromagnetic coil to move translationally with respect to the fixed-pole magnet. A gripper of some type is attached to the coil and moves with the moving coil. In use, the gripper is positioned over the component and advanced, under control of the coil, until contact between the gripper and the component has been established. The gripper is then caused to grasp the component. Subsequently, the gripper and component may then be translationally repositioned under control of the electromagnetic coil Additionally, the entire actuator, gripper, and component may be moved laterally, rotated, or otherwise relocated to further reposition the component.
In general, these linear voice coil actuators have proven to be an effective way for repositioning components. However, traditional gripper designs have not proven to be entirely satisfactory for asymmetric or irregularly shaped components. This problem is compounded by variations in the physical dimensions of successive components and/or variations in the pick-up position of components. In such cases, traditional gripper designs may be unable to effectively adapt to the differing components and differing positions, thereby making the components difficult to grasp and difficult to accurately manipulate.
Another potential difficulty arises when a particular process requires that a component be given a precise lateral alignment prior to insertion or other manipulation. Examples of processes of this type include the assembly of microelectronics, which require that extremely small packages be laterally located with great precision. Traditional grippers, however, include no apparatus specifically designed to allow components to be laterally repositioned in this fashion. Instead, lateral repositioning is traditionally accomplished by selectively moving the entire actuator and the component. In some cases, however, the size of the moving actuator, which may be much larger than the component itself, makes it difficult to achieve the accuracy required for a particular assembly operation.
Yet another potential difficulty arises when particularly fragile components must be picked up and manipulated. In many cases, where a traditional actuator is used in combination with a traditional gripper, there may be no way to determine the force applied by the gripper as the gripper grasps the component. As a result, fragile components may be damaged if an overabundance of force is applied by the gripper during the assembly process.
In light of the above, it is an object of the present invention to provide an actuator and gripper for use in an automated process which is adaptable to grasp irregular components. It is another object of the present invention to provide an actuator and gripper for use in an automated process which adapts to grasp components of varying dimensions, i.e., different sized components. Yet another object of the present invention is to provide an actuator and gripper for use in an automated process which provides accurate lateral positioning of the component. Another object of the present invention is to provide an actuator and gripper for use in an automated process which may be used in combination with fragile components. Another object of the present invention is to provide an actuator and gripper for use in an automated process which determines whether a component has been accurately and properly engaged by the actuator and gripper. Still another object of the present invention is to provide an actuator and gripper for use in an automated process which is relatively simple to use, is relatively easy to manufacture and is comparatively cost effective.